I have seen that say a CPU when overclocked and it exceeds its stability point at stock voltage(e.g. A 3.0 GHz CPU max stable at 3.7 GHz at stock volts) malfunctions the way an aged(dying) CPU does. Does this mean that a CPU having more overclocking headroom(space between the failure start frequency and stock frequency) has a greater lifespan(MTBF) than the same CPU having a less overclocking headroom at stock voltage considering both operate at stock freq and voltages?

I have seen that say a CPU when overclocked and it exceeds its stability point at stock voltage(e.g. A 3.0 GHz CPU max stable at 3.7 GHz at stock volts) malfunctions the way an aged(dying) CPU does. Does this mean that a CPU having more overclocking headroom(space between the failure start frequency and stock frequency) has a greater lifespan(MTBF) than the same CPU having a less overclocking headroom at stock voltage considering both operate at stock freq and voltages?

Click to expand...

Technically, yes, a better chip will last longer.

At stock, current chips should last 3x the warranty period, or about 10 years or more. I think a board would fail first, might take the CPU with it. MOSFETs/Capacitors are the most likely thing to fail, IMHO.

Exactly. These IVB chips are pretty tough, I must say, 1.15V stock, and I push 1.4 V on air no problem. That's like a what...25% voltage boost? Power draw goes from ~~70 W to 120W...near double...and only a 25% boost in clocks.

LOL yes. Actually the thing is the maximum overclocking efficiency is there when you are at stock volts only but push clocks at the max. That way you are actually getting more speed without using more power.

For me, it was even better. I clocked my Phenom II X4 955 at 3.7 GHz using 1.375V(undervolted 1.4V stock) and never had a problem. However just for a mere 200 MHz more that is 3.9 GHz I had to set the voltage to 1.45V or 1.378 V LLC on as in my specs. For another 100 MHz, I need greater than 1.5 V even(less when LLC on).

CPU lifetime is calculated at continuous full load, at a stock voltage range and at a certain temperature (varies by CPU type). Lower any of the three, and you get quite an extension of that predicted life. CPU warranty period is the absolute worst-case scenario of all parameters. As it has been said, in a typical usage scenario, a CPU will be long obsolete before it dies.

On the other hand, LN2 and > 50% overvolting + ~100% overclocking will usually bring the lifetime down quite considerably. I've seen actual examples of this, though it was just certain parts of the CPU failing (just one of the cores, or the L3 cache), never seen an entire CPU outright stop working. It is worth noting that going sub-zero is as bad as going over 50°C, because you increase the electrical conductivity of the P-N junctions, which makes electromigration danage spike to problematic levels.

I thought the lifespan had to do with electromagnetic mitigation that increased with temps, so that if you had lower temps it would increase the lifespan. I do not have a source for this, I just remember from something I read quite some time ago.